UPS, which was founded in 1907 in Seattle, Washington, makes 7.7 million deliveries each day and employs 398,300 people worldwide. Last year its revenue was $53.1 billion.

The company's clout means Davis' comments are closely watched, as they were when he said the U.S. economy would grow less than expected during a call with analysts.

The company is a "barometer of what is going on in the U.S. economy," Davis said.

He believes the U.S. economy will grow, but at a very slow pace. "I think uncertainty will continue into the second half of the year," Davis said.

And while uncertainty in tax policy and spending policy remains, businesses "are not going to hire people, they won't invest, and I think that will slow things down for the next six months until we make decisions in Washington," he added.

Despite the crisis, Europe's economy is showing improvement. "It actually has been reasonably good for UPS in Europe," Davis noted. "It is slowing, as we saw earlier in the year, but we are still showing growth in Europe."

"Our idea is to invest in TNT, [and] people look at me as if to say, 'are you crazy, a European acquisition at this time?' "Davis said.

But UPS is a long term investor, he added. "We think Europe will be fine in the long term, we think it will have a rough turbulent couple of years, but long-term Europe will be competitive and do fine."